<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin:0 auto;
        }
        .center,
        .left,
        .right {
            padding-bottom: 10000px;
            margin-bottom: -10000px;
        }
        .container{
            /* 为左右腾出空间 */
            padding-left:200px;
            padding-right:200px;
            overflow: hidden;
            /* //把溢出背景切掉 */
        }
        .conter{
            width:100%;
            height:500px;
            background: plum;
            float:left;
        }
        .left{
            float:left;
            width:200px;
            height:400px;
            background:red;
            margin-left:-100%;
            position: relative;
            left:-200px;
        }
        .right{
            float:left;
            width:200px;
            height:400px;
            background: cadetblue;
            margin-left:-200px;
            position: relative;
            right:-200px;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="conter">
            <h1>圣杯布局</h1>
        </div>
        <div class="left"></div>
        <div class="right"></div>
    </div>
</body>
</html>